FI69983B - PROCEDURE FOR THE FRAMEWORK FOR FORMARING AND UNDERSTANDING OF MEASURES - Google Patents

Description

69983

Method of manufacturing a mold for use in vacuum forming or blow molding

In vacuum molding or blow molding, a plastic sheet heated in a plastic space is placed over the mold so that the outer edges of the sheet press tightly against the mold. Thereafter, in the vacuum forming, the air between the plate and the mold is sucked out of the small suction holes in the mold, so that the plate is tightly absorbed on the surface 10 of the mold. When blowing into the mold, the plate is again pressed against the surface of the mold with overpressure.

All-metal molds or metal-faced molds made by machining or casting have been used as the mold, with the metal layer being grown on the mold surface 15 either electrolytically or by injection, and the metal layer supported by a cast epoxy resin or epoxy-resin aluminum crumb mixture.

The present invention relates to a mold made by injection, the most significant disadvantages of which have been the need for the above-mentioned backing, since the sprayed brittle and porous shell has not been strong enough without this support. Additional disadvantages are, in particular, the poor thermal conductivity of the epoxy resin backing, due to which the mold shell easily detaches from the support due to rapid thermal expansions. The brittle, sprayed shell also cracks easily. The electrolytically produced shell is not as brittle as the sprayed one, but it is slow and expensive to manufacture and always remains so thin that it requires backing, so it therefore has the disadvantages mentioned above. In addition, as with expensive machining and casting molds, it has additional disadvantages, such as limited size and limited shapes.

The present invention relates to a method of manufacturing a mold for metal or steel injection, either wire or powder injection, for use in the vacuum forming or blow molding of a thermoplastic material, the essential features of which are set forth in U.S. Pat.

69983 claims. A mold made according to the method does not need the backing made of pulp described above, so detachment does not cause the shell to break. The thermal conductivity of the entire mold is good, so the mold 5 withstands rapid heat fluctuations without cracking and retaining its shape well enough. The surface of the mold meets the tightness requirements set for it, and the shape of the surface can be changed somewhat even afterwards. It is also possible to make much larger molds than before.

The method of manufacturing the mold is described in detail below with the aid of a schematic diagram: 1. the basic model 1 made can be of any material which can withstand short-term heat + 100 ° C 15 2. a layer of separator is sprayed on the surface of model 1 a metal mesh 3 or wires 5 20 are placed on top of the metal layer 2. 4. a new injection is made2 5. this is repeated 5 ... 50 times until the mesh 3 or wires are covered 6. if necessary a cooling pipe 4 is placed on the metal surface 25 7. the metal 2 is covered again 10 ... by spraying 50 times 8. reticulate the surface 5 9. spray again 10 ... 100 times with metal 2 until the mold has the mold strength required for each method.

If the mold has surfaces close to the plane or is considerably large, a stronger metal mesh or stronger metal wires and more spray times, even more than the above, are required. The metal mesh or -35 wires and the cooling piping must be the same or have a coefficient of thermal expansion similar to that of the injection metal.

The manufacturing method is mainly comparable to the method

Claims (3)

5 7.) 69983 for the production of steel wire reinforced concrete or fiberglass reinforced reinforced concrete. A method of manufacturing a mold for vacuum forming or blowing a thermoplastic material into a mold, wherein the mold is made by spraying metal or steel on the surface of the base model (1) with either a wire or powder sprayer, characterized in that a metal mesh ( 3) or yarns, followed by re-injection of 15 nets or yarns 5-50 times (2). A method of manufacturing a mold according to claim 1, characterized in that a cooling piping (4) is placed on top of the spraying layer covering the net or wires 20, after which a re-injection covering the piping is performed 10-50 times. A method of manufacturing a mold according to claim 1 or 2, characterized in that new or new metal nets (5) or wires are placed on top of the metal layer covering the metal mesh or wires or cooling piping, which is covered by a new covering of the mesh or wires. metal rye-30 spawning 5-50 times each time.